Snowpack Summary published on March 15, 2021 @ 9:49 am
Issued by Sue Burak - Bridgeport Avalanche Center

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Fresh wind drifts began forming last night and will continue to develop this morning. As of this morning, 3 inches of snow have fallen in the lower elevations of Virginia Lakes with 9 inches falling in the Leavitt Lake area. Snowpack stability will vary considerably with the terrain as snow continues to fall during the day.  Be on the lookout for signs of wind slabs such as smooth, drifted snow, cracking or whumpfing on steep NW-SE facing slopes, especially under ridgetops and convex terrain features. 

Avalanche Character 1: Wind Slab
Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas.

Strong southwest winds continue to create wind slabs and areas of wind drifted snow in exposed alpine terrain. Wind slabs will also be found near treeline, especially in the McKay Creek drainage. You will also  find small to large wind slabs on north and east facing gullies and areas below ridges or cliffs, such as the bowls above Leavitt and Koenig Lakes.  

Snowpack Discussion

Another cold spring storm will drop a few more inches of snow in the forecast area. On Saturday, new snow was bonding to old snow surfaces well even on wind loaded slopes. Riders in the BWRA and Virginia Lakes area enjoyed good riding conditions last weekend.  The current storm will produce a few more inches of snow before clear and dry weather returns. Wind directions shift from the southwest to the north and northwest later today. South facing slopes around the caves near Latopie Lake could also see small wind slabs formation if snow continues to fall and northerly winds transport more snow.


Smooth and convex areas of drifted snow look great to ride but are areas where triggering a small avalanche is possible.  Avoiding these areas is the best defense against avalanches today. Signs that  wind slabs are sensitive to triggering include visible cracking, whumpfing noises and collapsing. Avoid areas of drifted snow or places that appear smooth and convex. Human triggered wind slab avalanches may be possible today in steep windloaded terrain. Avalanches will likely be small but larger slides are possible.

CURRENT CONDITIONS Weather observations from Sonora Pass
0600 temperature: 9 deg. F.
Max. temperature in the last 24 hours: 38 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 35 mph
Maximum wind gust in the last 24 hours: 80 mph
New snowfall in the last 24 hours: 5-9" inches
Total snow depth: 102 inches

This morning, strong south winds are blowing 60-80 mph. Light snow is falling along the Sierra crest and down to the 395 corridor. As the day progresses winds will begin to transition around the compass rose, by mid afternoon wind will be blowing from the W and before dark the wind is forecasted to come in from the N. Snow will continue to fall throughout the day at higher elevations above 10k could see 3-5 in. Temperatures will be in the high teens low 20s at that elevation as well.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8000 ft. to 10000 ft.
  Monday Monday Night Tuesday
Weather: winds and light snow, thunder possible showers, clearing later in the evening clear skies
Temperatures: 18 deg. F. 10 deg. F. 34 deg. F.
Wind direction: SW NE W
Wind speed: 15 10-15 10
Expected snowfall: 1-3 in. 0 in. 0 in.
For above 10000 ft.
  Monday Monday Night Tuesday
Weather: snow showers and breezy snow showers sun
Temperatures: 17 deg. F. 16 deg. F. 33 deg. F.
Wind direction: SW N W
Wind speed: 15-35 15-20 25
Expected snowfall: 1-3 in. 0 in. 0 in.

This snowpack summary applies only to backcountry areas in the Bridgeport Winter Recreation Area. Click here for a map of the area. This snowpack summary describes general avalanche conditions and local variations always occur. This snowpack summary expires in 48 hours unless otherwise noted. The information in this snowpack summary is provided by the USDA Forest Service who is solely responsible for its content.